<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <!-- 注释 -->
  <div class="qwer">
    123
  </div>
  <div class="test">456</div>

  <script>

    // 节点： 标签  属性  文本 注释
  </script>
</body>
</html>